I think those are a nice start for some MVP system but any one probably would need more fleshing out, especially if you want to make a competitive product.

i.e. in a few of the library datanases, book identifcation using ISBN, ISBNs can change by revision also does not adequately handle tracking multiple copies. But I can see these can give you a glimpse of what datasets you will be concerning yourself with.

I spend my time working on the client side of the browser. Can someone with more knowledge tell me how good these data models are? Are they good quality and worth studying?

Looks like a really good resource. Thanks, I'll start with this. I wish there were more resources like this.

Great info. This site has compiled a quite good numbers of database designs. Thank you.

That's quite a nifty resource

This is gold. Thanks for sharing

Awesome, thanks!